GS1524-CTDE3(2011) 데이터 시트보기 (PDF) - Gennum -> Semtech
부품명
상세내역
제조사
GS1524-CTDE3 Datasheet PDF : 16 Pages
| |||
5. Detailed Description
The GS1524 is a high speed bipolar IC designed to equalize both HD and SD serial digital
signals. The device can typically equalize greater than 140 meters of Belden 1694A cable
at 1.485Gb/s and 350m at 270Mb/s. Powered from a single +3.3V or -3.3V power supply,
the device consumes approximately 265mW of power.
5.1 Serial Digital Inputs
The serial data signal may be connected to the input pins (SDI/SDI) in either a
differential or single ended configuration. AC coupling of the inputs is recommended, as
the SDI and SDI inputs are internally biased at approximately 1.8V.
5.2 Cable Equalization
The input signal passes through a variable gain equalizing stage whose frequency
response closely matches the inverse of the cable loss characteristic. In addition, the
variation of the frequency response with control voltage imitates the variation of the
inverse cable loss characteristic with cable length.
The edge energy of the equalized signal is monitored by a detector circuit which
produces an error signal corresponding to the difference between the desired edge
energy and the actual edge energy. This error signal is integrated by both an internal and
an external AGC filter capacitor providing a steady control voltage for the gain stage. As
the frequency response of the gain stage is automatically varied by the application of
negative feedback, the edge energy of the equalized signal is kept at a constant level
which is representative of the original edge energy at the transmitter. The equalized
signal is also DC restored, effectively restoring the logic threshold of the equalized signal
to its correct level independent of shifts due to AC coupling. The digital output signals
have a nominal voltage of 750mVpp differential, or 375mVpp single ended when
terminated with 50Ω as shown in Figure 5-1.
+187.5mV
SDO
VCM = 2.925V
typical
-187.5mV
SDO
50 50
+187.5mV
VCM = 2.925V
typical
-187.5mV
Figure 5-1: Typical Output Voltage Levels
GS1524 Multi-Rate SDI Adaptive Cable Equalizer
Data Sheet
14976 - 11
August 2011
12 of 16
Share Link: 